Mission Accomplished. The spacecraft sent by NASA to deflect the trajectory of an asteroid with the impact of the collision has succeeded, in an innovative test of “planetary defense” that should better protect Earth from a possible future threat.
The spacecraft, which is no bigger than a car, collided at the expected time (20:14 GMT) with the asteroid at more than 20,000 km/h.
NASA teams, gathered at the mission control center in Maryland, exploded with happiness at the spectacular images of the approaching asteroid Dimorphos until just before impact.
In the live stream, it was possible to clearly distinguish the rocks on the gray surface of the asteroid, 11 million kilometers from Earth.
“We are embarking on a new era where we potentially have the ability to protect ourselves from a dangerous asteroid impact,” said Lori Glaze, NASA’s director of planetary science.
Dimorphos measures about 160 meters in diameter and poses no danger to our planet. The target is actually the satellite of another larger asteroid, Didymos, around which it orbits in 11 hours and 55 minutes. NASA was looking to reduce its orbit by ten minutes to bring it closer to Didymos.
It will take several days or perhaps weeks for scientists to confirm that the asteroid’s trajectory has indeed changed, which will be done thanks to telescopes on Earth that will observe the change in brightness as the smaller asteroid passes in front of or behind the larger one.
While the goal is still modest compared to science fiction movies like “Armageddon,” this “planetary defense” mission dubbed DART allows NASA to train in case a large asteroid threatens to one day impact Earth. Earth.
Integrated camera
The spacecraft has traveled for ten months since its launch in California.
To hit such a small target, it was piloted autonomously for the last four hours of the journey, like a self-guided missile.
Three minutes after the impact, a shoebox-sized satellite, called LICIACube, and launched by DART a few days ago, reportedly passed within approximately 55 km of the asteroid to capture images of the collision, which will be sent to Earth in the coming weeks and months.
The event was also observed by the Hubble and James Webb space telescopes, which are expected to detect a cloud of glowing dust.
All this should allow a better understanding of the composition of Dimorphos, representative of a population of very common asteroids and, therefore, to measure the effect that this technique, called kinetic impact, can have on them.
Unknowns
Asteroids have surprised scientists in the past.
In 2020, the American probe Osiris-Rex sank deeper than expected on the surface of asteroid Bennu.
Currently, the porosity of Dimorphos is unknown. “If the asteroid responds to the DART impact in a totally unforeseen way, it could actually lead us to reconsider the extent to which kinetic impact is a generalizable technique,” said Tom Statler, the mission’s chief scientist.
No known asteroids threaten Earth for the next hundred years.
Around 30,000 asteroids of all sizes have been cataloged in its vicinity, which are called near-Earth objects, that is, whose orbit crosses the Earth.
Those a kilometer or more were almost all spotted, according to scientists. But they estimate that only about 40% of asteroids measuring 140 meters or more capable of devastating an entire region are known.
“Our most important job is to find” the missing ones, said Lindley Johnson, NASA’s planetary defense officer.
The sooner they are detected, the more time experts have to determine how best to defend against them.
But the DART mission is a crucial first step, Johnson said: “It’s a very exciting time … for space history, and even for human history.”
